/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package dev.metaschema.core.metapath.function.library;
   
   import java.util.List;
   import java.util.Set;
  
  import dev.metaschema.core.metapath.DynamicContext;
  import dev.metaschema.core.metapath.MetapathConstants;
  import dev.metaschema.core.metapath.function.FunctionUtils;
  import dev.metaschema.core.metapath.function.IArgument;
  import dev.metaschema.core.metapath.function.IFunction;
  import dev.metaschema.core.metapath.item.IItem;
  import dev.metaschema.core.metapath.item.ISequence;
  import dev.metaschema.core.metapath.item.atomic.IDateItem;
  import dev.metaschema.core.metapath.item.atomic.IStringItem;
  import dev.metaschema.core.util.ObjectUtils;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  
  /**
   * Implements the XPath 3.1 <a href=
   * "https://www.w3.org/TR/xpath-functions-31/#func-format-date">fn:format-date</a>
   * functions.
   *
   * @see <a href=
   *      "https://www.w3.org/TR/xpath-functions-31/#func-format-date">XPath 3.1
   *      fn:format-date</a>
   */
  public final class FnFormatDate {
    private static final String NAME = "format-date";
  
    /**
     * The set of component specifiers allowed for date values, which excludes
     * time-only markers (H, h, P, m, s, f).
     */
    @NonNull
    static final Set<Character> DATE_MARKERS = Set.of(
        'Y', 'M', 'D', 'd', 'F', 'W', 'w',
        'Z', 'z', 'C', 'E');
  
    @NonNull
    static final IFunction SIGNATURE_TWO_ARG = IFunction.builder()
        .name(NAME)
        .namespace(MetapathConstants.NS_METAPATH_FUNCTIONS)
        .deterministic()
        .contextDependent()
        .focusIndependent()
        .argument(IArgument.builder()
            .name("value")
            .type(IDateItem.type())
            .zeroOrOne()
            .build())
        .argument(IArgument.builder()
            .name("picture")
            .type(IStringItem.type())
            .one()
            .build())
        .returnType(IStringItem.type())
        .returnZeroOrOne()
        .functionHandler(FnFormatDate::executeTwoArg)
        .build();
  
    @NonNull
    static final IFunction SIGNATURE_FIVE_ARG = IFunction.builder()
        .name(NAME)
        .namespace(MetapathConstants.NS_METAPATH_FUNCTIONS)
        .deterministic()
        .contextDependent()
        .focusIndependent()
        .argument(IArgument.builder()
            .name("value")
            .type(IDateItem.type())
            .zeroOrOne()
            .build())
        .argument(IArgument.builder()
            .name("picture")
            .type(IStringItem.type())
            .one()
            .build())
        .argument(IArgument.builder()
            .name("language")
            .type(IStringItem.type())
            .zeroOrOne()
            .build())
        .argument(IArgument.builder()
            .name("calendar")
            .type(IStringItem.type())
            .zeroOrOne()
            .build())
        .argument(IArgument.builder()
            .name("place")
            .type(IStringItem.type())
            .zeroOrOne()
            .build())
        .returnType(IStringItem.type())
       .returnZeroOrOne()
       .functionHandler(FnFormatDate::executeFiveArg)
       .build();
 
   private FnFormatDate() {
     // disable construction
   }
 
   @SuppressWarnings("unused")
   @NonNull
   private static ISequence<IStringItem> executeTwoArg(
       @NonNull IFunction function,
       @NonNull List<ISequence<?>> arguments,
       @NonNull DynamicContext dynamicContext,
       IItem focus) {
 
     IDateItem value = FunctionUtils.asTypeOrNull(arguments.get(0).getFirstItem(true));
     if (value == null) {
       return ISequence.empty();
     }
 
     IStringItem picture = FunctionUtils.asType(
         ObjectUtils.requireNonNull(arguments.get(1).getFirstItem(true)));
 
     String lang = dynamicContext.getStaticContext().getDefaultLanguage();
 
     return ISequence.of(IStringItem.valueOf(
         formatDate(value, picture.asString(), lang, null, null)));
   }
 
   @SuppressWarnings("unused")
   @NonNull
   private static ISequence<IStringItem> executeFiveArg(
       @NonNull IFunction function,
       @NonNull List<ISequence<?>> arguments,
       @NonNull DynamicContext dynamicContext,
       IItem focus) {
 
     IDateItem value = FunctionUtils.asTypeOrNull(arguments.get(0).getFirstItem(true));
     if (value == null) {
       return ISequence.empty();
     }
 
     IStringItem picture = FunctionUtils.asType(
         ObjectUtils.requireNonNull(arguments.get(1).getFirstItem(true)));
     IStringItem language = FunctionUtils.asTypeOrNull(arguments.get(2).getFirstItem(true));
     IStringItem calendar = FunctionUtils.asTypeOrNull(arguments.get(3).getFirstItem(true));
     IStringItem place = FunctionUtils.asTypeOrNull(arguments.get(4).getFirstItem(true));
 
     return ISequence.of(IStringItem.valueOf(
         formatDate(
             value,
             picture.asString(),
             language == null ? dynamicContext.getStaticContext().getDefaultLanguage() : language.asString(),
             calendar == null ? null : calendar.asString(),
             place == null ? null : place.asString())));
   }
 
   /**
    * Format a date value using a picture string per the XPath 3.1 <a href=
    * "https://www.w3.org/TR/xpath-functions-31/#func-format-date">fn:format-date</a>
    * specification.
    *
    * @param value
    *          the date value to format
    * @param picture
    *          the picture string
    * @param language
    *          the language, or {@code null}
    * @param calendar
    *          the calendar, or {@code null}
    * @param place
    *          the place, or {@code null}
    * @return the formatted string
    */
   @NonNull
   public static String formatDate(
       @NonNull IDateItem value,
       @NonNull String picture,
       @Nullable String language,
       @Nullable String calendar,
       @Nullable String place) {
     return DateTimeFormatUtil.formatDateTime(value, picture, language, calendar, place, DATE_MARKERS);
   }
 }